title: Separation of multiphosphorylated peptide isomers by CZE.
abstract: A separation of mono, doubly and triply phosphorylated isomers was developed with CZE with an aqueous electrolyte containing 3.9 mol/L formic acid and 30% v/v trifluoroethanol. Thus a mixture of ten phosphopeptides corresponding to the human tau sequence 226-240 was separated within 70 min. Although peptides with different phosphorylation degrees, i.e. 0-3 phosphate groups, were well separated, some of the phosphopeptide isomers containing one or two phosphate groups were only partially separated. The electrolyte system is compatible with both MALDI- and ESI-MS, allowing a direct coupling, and thus could have some interesting applications in proteomics.
authors.affiliation: Institute of Bioanalytical Chemistry, Center for Biotechnology and Biomedicine, Faculty of Chemistry and Mineralogy, Leipzig University, Leipzig, Germany.
authors.forename: Marika V
authors.initials: MV
authors.lastname: Muetzelburg
authors.forename: Ralf
authors.initials: R
authors.lastname: Hoffmann
mesh_terms: D000595:Amino Acid Sequence; D004573:Electrolytes; D019075:Electrophoresis, Capillary; D005561:Formates; D006801:Humans; D007202:Indicators and Reagents; D007536:Isomerism; D008969:Molecular Sequence Data; D010748:Phosphopeptides / Q000032:analysis*; D010766:Phosphorylation; D014270:Trifluoroethanol; D016875:tau Proteins / Q000032:analysis*
chemical_list: D004573:Electrolytes; D005561:Formates; D007202:Indicators and Reagents; D010748:Phosphopeptides; D016875:tau Proteins; C030544:formic acid; D014270:Trifluoroethanol